Electronic devices, which include a portable terminal, are designed to support specific user functions and maintain a size sufficiently small in order for the user to carry around in a pocket or purse. The increased functionality and decreased size and power usage has caused portable terminals to become very popular to the general public. Further, in recent years, portable terminal referred to as “smart phones” that integrally supporting various user functions beyond voice and text have been introduced. Such a portable terminal provides an image corresponding to a user function through a display unit while supporting the user function. Thus, when a user accesses a specific user function, the user accesses the specific user function while looking at the image displayed through the display unit.
Meanwhile, a portable terminal according to the related art can be configured to support a writing or painting function through an electromagnetic induction pen. In this case, the induction pen supports a function of a terminal detecting a specific input signal while the pen is placed on a display unit according to display characteristics. Thus, in the state of gripping the pen, the user operates the pen on the display unit of the terminal to perform the writing function. Since there are many different angles at which each user grips pens, and users can be left-handed as well as right-handed, there is a user difference between points identified by the, the various ways the pen is held. The display unit and the terminal recognizes the position of the pen in a certain and the various different types of slanting causes an error while using the pen. In order to solve the problem, a scheme of applying a predetermined offset in consideration of the distance between a place of the pen and a nib of the pen has been proposed in the related art. However, although the proposed scheme can be suitable for a specific situation, it is difficult to suitably apply the scheme to various situations in which the terminal is operated and the pen is used. As a result, a currently used pen technique does not compensate for various errors and that are based user idiosyncrasies and characteristics, as well as the usage state of the particular terminal.